磁共振增强扫描序列在合并阻塞性肺炎或肺不张肺癌放疗靶区勾画价值

目的探讨MRI不同序列在肺癌伴阻塞性肺炎或肺不张(OC)患者中进行靶区勾画的可行性及优势。方法对14例合并OC患者行CT定位和MRI扫描,分别采集CT、T1WI、压脂T2WI、LAVA、LAVA+C图像。将CT、MRI图像在治疗计划系统中融合,分别在CT和MRI上进行靶区勾画GTV-p。结果CT可显示2例患者肿瘤与OC界限,压脂T2WI可显示10例患者肿瘤与OC界限,LAVA可显示12例患者肿瘤与OC界限,LAVA+C可显示10例患者肿瘤与OC界限。压脂T2WI、LAVA、LAVA+C序列间鉴别能力相近(P>0.05),T2WI、LAVA、LAVA+C序列GTV均较CT-GTV明显减小(P<0.05),T2WI_GTV和LAVA_GTV相近(P>0.05)。在所有序列中LAVA+C的GTV值最小。结论MRI的压脂T2WI、LAVA、LAVA+C序列应用于肺癌伴OC患者的放疗靶区勾画提高了精准性,其中LAVA的界限分辨能力较压脂T2WI更好,LAVA+C显示微小血管效果最好。

The value of MRI enhanced scan sequence in the radiotherapy target volume delineation in lung cancer with obstructive pneumonia/atelectasis

Objective To explore the feasibility and advantages of different MRI sequences in delineating target volumes in lung cancer with obstructive pneumonia or atelectasis (OC). Methods Fourteen patients with OC underwent CT localization and MRI scan. CT, T1WI, fat suppression T2WI, LAVA, LAVA+C images were collected respectively. CT and MRI images were fused in the treatment planning system, and GTV-p was target delineated on CT and MRI respectively. Results CT showed tumor and OC boundaries in 2 patients, fat suppression T2WI showed tumor and OC boundaries in 10 patients, LAVA showed tumor and OC boundaries in 12 patients, and LAVA+C showed tumor and OC boundaries in 10 patients. Fat suppression T2WI, LAVA, and LAVA+C sequences showed similar resolving ability (P>0.05). The GTV of T2WI, LAVA, and LAVA+C sequences decreased significantly compared with ST-GTV (P<0.05), and T2WI_GTV and LAVA_GTV were similar (P>0.05). The GTV value of LAVA+C was the smallest among all sequences. Conclusions The application of MRI fat compression T2WI, LAVA, and LAVA+C sequences to the radiotherapy target volume delineation in lung cancer patients with OC improved the accuracy, among which the boundary resolution of LAVA was better than that of fat compression T2WI, and LAVA+C showed the best effect on tiny blood vessels.